In many fields of applications it is important that save coupling between connectors and corresponding counter connectors can be guaranteed. In particular in the case of automotive safety restraint systems as for example airbag systems in passenger vehicles, plug connectors used for the connection of an airbag to its ignition base, i.e. to a squib socket, have to be provided with reliable safety systems. Typically, to this end these plug connectors are provided with connector position assurance (CPA) members which can be inserted into a locked position on the plug connector only if the plug connector is appropriately connected to the airbag squib socket. In this position, the CPA member provides additional security for the mated state of plug connector and squib socket, and typically the CPA member is constructed such that an operator can visibly detect if the CPA member is inserted correctly into its locked position. Thus, thereby a correct and safe mating between the connector and the counter connector can be guaranteed.
An example of a plug connector provided with a CPA member is disclosed in document EP 1207591 A2. Therein, a plug connector is described which can be connected to a squib socket of an airbag connector system. In assembled condition, when the plug connector is inserted into the airbag squib socket, the plug connector is fixed inside the socket by means of flexible latching arms. During insertion of the plug connector into the socket, these arms bend inwardly until locking projections provided on the latching arms snap into corresponding latching recesses of the airbag squib socket.
In order to further secure the mating of the plug connector with the airbag squib socket a CPA member is provided. When the plug connector is inserted into the airbag squib socket and the locking projections are snapped into the latching recesses, the CPA member can be inserted into a housing of the plug connector. The CPA member comprises locking arms which upon insertion move into slots in between faces of the plug connector housing and the latching arms. Once these locking arms are inserted into the slots, bending of the latching arms is blocked and thus the latching arms are fixed inside of the recesses and the mating of plug connector and airbag squib socket is secured. According to EP '591, only when the connectors are correctly mated, the CPA member can be moved into the locked position in which it secures the mated state of the connectors. This can be visibly detected by an operator and thus it is possible to guarantee the correctly mated state of the connectors.
Even though the solution as proposed in the EP '591 works satisfactory, for certain applications the use of a CPA member is undesirable for example because of space limitations. An example of a plug for the connection to a squib socket without a CPA member is disclosed in document DE 20216337 U1. The plug connector disclosed therein is an example of a so called “scoop-proof” plug connector which is provided with a connection tube surrounding electrical contacts of the plug connector. This connection tube is designed such that upon mating of the plug connector to a squib socket, contact terminals of the plug connector can be connected only correctly to corresponding contact pins of the airbag squib socket. In the case that the plug connector is not correctly inserted into the airbag squib socket, the connection tube abuts the airbag squib socket such that false connection of the contact terminals to the contact pins is prevented.
To mechanically connect the plug connector to a squib socket, the plug connector is provided with latching arms which are attached to the connection tube such that upon insertion of the plug connector into the socket, the latching arms bend inwardly and upon full insertion of the plug connector into the airbag squib socket, locking projections provided on the latching arms snap into corresponding latching recesses of the airbag squib socket.
A further example of a plug connector to be connected to a squib socket without a CPA member is disclosed in document EP 2230731 A1. Therein, similar to the above described example, a “scoop-proof plug connector is described whereby this plug connector can be connected to a corresponding squib socket by means of latching arms which are mounted to flexible portions provided on a connection tube of the plug connector. Due to the flexibility of the latching arms, upon insertion of the plug connector into the airbag squib socket, the locking arms bend inwardly and upon full insertion of the plug connector, locking projections provided on the latching arms snap into recesses of the socket to lock the plug connector to the airbag squib socket.
The latching arms of the EP '731 are further provided with release members which, in mated condition of the plug connector with the airbag squib socket, can be actuated by an operator, i.e. they can be pressed inwardly to release the locking projections from the locking recesses. Thereby, the plug connector is free to be removed from the socket. Even though the latter two plug connectors are provided with reliable locking mechanisms and can be connected to squib sockets without CPA members, both plug connectors lack the possibility to visibly detect the mated state of the plug connectors to squib sockets.
The subject matter discussed in the background section should not be assumed to be prior art merely as a result of its mention in the background section. Similarly, a problem mentioned in the background section or associated with the subject matter of the background section should not be assumed to have been previously recognized in the prior art. The subject matter in the background section merely represents different approaches, which in and of themselves may also be inventions.